A facial expression results from one or more motions or positions of the muscles of the face. These movements【C1】______ the emotional state of the individual to observers. Facial expressions are a form. of nonverbal communication. They are a【C2】______ means of expressing social information among humans, but also occur【C3】______most other mammals and some other animal species. Facial expressions and their significance in the【C4】______ can, to some extent, vary between cultures. Peoples expressions are often shaped by artists. Through this method, ones spirit can be showed【C5】______. Humans can【C6】______a facial expression as a voluntary action. However, because expressions are closely【C7】______ to emotion, they are more often involuntary. It can be nearly impossible to avoid expressions for certain emotions, even when it would be strongly【C8】______to do so: a person who is trying to avoid【C9】______ to an individual he or she finds highly unattractive might【C10】______ show a brief expression of disgust before being able to reassume a【C11】______ expression. The close link between emotion and expression can also work in the other direction.【C12】______some researchers have observed in some cases, voluntarily assuming an expression can actually cause the associated emotion. Some expressions can be accurately【C13】______ even between members of different species—anger and extreme contentment【C14】______ the primary examples. Others, however, are difficult to understand even in familiar individuals. For instance, disgust and fear can be tough to tell【C15】______. Because faces have only a limited range of movement, expressions【C16】______fairly minuscule differences in the proportion and relative position of facial features, and reading them requires considerable【C17】______. Some faces are often【C18】______ read as expressing some emotion, even when they are neutral, because their proportions naturally【C19】______ those another face would【C20】______assume when emoting. 【C1】